In this dissertation, high throughput approaches for diffusion and oxidation processes for silicon solar cell manufacturing are investigated. The focus lies on developing sustainable processes or process combinations for PERC and TOPCon solar cells which enable higher throughputs and reduced energy consumption than state-of-the-art processes at comparable energy conversion efficiency level. High throughput is reached by increasing the wafer load in the process using wafer stacks, where the wafer surfaces are touching each other. The interactions between phosphorus diffusion and thermal oxidation of the stack process approach are examined in detail. Further, a hypothesis for the oxygen gas transport mechanism into the wafer gap is stated and confirmed by experiments and simulation. Further understanding of the stack diffusion approach is generated when investigating boron-doping processes.